''THEIR'' relationship has transcended the sexual desires, there is no need even for words for them, Ran trips and drops the sweets she made and Keiko, without even questioning anything like most would do, picks some up and eats them.
Yeah, well, any friend in any manga would have done the same thing.
Uhm, no? Ran was established as this free spirit, lots of energy, lots of genkiness and somewhat of an potty mouth but with good intentions, always dragging Keiko to things with her energy, so when she suddenly trips most people would have written this scene like this: ''Oh man Ran, you are so clumsy'' but Keiko doesn't even questions it anymore and just goes to the option that would make her happy, that's as subtle as you can get.
My point was that, no matter how fitting the pieces look, they won't necessarily come together, I can understand that the story looks like it's stopped in it's track but Shou kinda wrote himself into a corner here because there is really next to no way to make the romantic-option look like a logical next step, sure the shippers would be happy but there are plenty of people that don't want to see them together because they don't really see the point in it when they are getting along just fine.